What Belongs in Your Page Source, and What Does Not
Most of what a browser receives is never seen by the person reading the page. It is instructions: what the page is about, how it should behave, what a search engine should make of it. Some of it is genuinely useful and some of it is clutter, and knowing the difference is worth a few minutes.
What should be there
A title and a description, distinct per page. A statement of which address is the canonical one. Structured data describing who the page is about, which is what lets a search engine understand that a page is about a person rather than guessing from the words. Response headers that tell the browser how to treat the content, covered in two security headers on every customer site.
All of that is invisible and all of it does work.
What should not
Three categories, and they are worth recognizing on any site, not only your own.
Anything about the server. A file path, a directory listing, a database name. None of it helps a visitor and all of it tells somebody more about how a site is put together than they need to know.
Debugging output. Console messages and diagnostic dumps left behind after somebody was solving a problem. Harmless individually, and cumulatively they read as a site nobody is tending.
Instructions that do nothing. This is the sneaky one. A directive written in the wrong place looks like a working setting and has no effect whatever. A privacy instruction that only functions as a response header does nothing at all when written as a tag in the page, and it will sit there for years looking like a policy while enforcing nothing.
How it gets caught
Every design is put through a standards validator and the results grouped by shape, so a bad attribute repeated sixteen times inside a loop reads as one finding with a count rather than sixteen separate lines. That is the difference between a report somebody reads and a wall of text somebody closes.
Not every warning is worth acting on, and pretending otherwise is its own trap. A cosmetic validation warning that would require a risky change to resolve is better left and documented than fixed for the sake of a clean report.
Related: how your photo galleries open, alt text on every image, how your stylesheets are assembled and GDPR compliance.
